Search results for "Astrophysical"
showing 10 items of 4966 documents
Search for contained neutrino events at energies greater than 1 TeV in 2 years of data
2015
The IceCube Neutrino Observatory was designed primarily to search for high-energy (TeV--PeV) neutrinos produced in distant astrophysical objects. Here we present the results of a search for neutrino interactions inside IceCube's instrumented volume between 1 TeV and 1 PeV in 641 days of data taken from 2010--2012. From these data we derive new constraints on the diffuse astrophysical neutrino spectrum,as well as the strongest upper limit yet on the flux of neutrinos from charmed-meson decay in the atmosphere.
Search for sterile neutrinos with one year of IceCube data
2016
The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy to search for the oscillation signatures of light sterile neutrinos. The primary result of this search derives from the first year of data, taken during 2011, of the full 86-string IceCube configuration.
IceCube Oscillations: 3 years muon neutrino disappearance data
2015
In the 1990s, Super-Kamiokande’s measurements of atmospheric neutrinos led to the acceptance of the mass-induced oscillation model. As of today, the three mixing angles, the solar mass splitting and the absolute value of the atmospheric mass splitting that control the oscillation phenomenon have been measured. We present a measurement of neutrino oscillations via atmospheric muon neutrino disappearance with three years of data of the completed IceCube neutrino detector. DeepCore, a region of denser instrumentation, enables the detection and reconstruction of atmospheric muon neutrinos between 10 GeV and 100 GeV, where a strong disappearance signal is expected.
Measurement of atmospheric neutrino oscillations with three years of data from the full sky.
2018
Initial release related to the measurement of atmospheric neutrino oscillations using three years of neutrino data from the full sky. IceCube results published in Physical Review Letters are competitive for the first time with the best measurements to date. Release limited to Δχ² maps in the (Δm², sin²(θ_23)) space for both the normal and inverted mass ordering. Additional information will be provided as follow-up data analyses are completed by the IceCube Collaboration.
Coherence in neutrino oscillations
2011
The theory of neutrino oscillations has turned out to be the most reasonable explanation to the observed violations in lepton number conservation of solar and atmospheric neutrino fluxes. A derivation of the most important results of this theory is first given using a plane wave treatment and subsequently using a three-dimensional shape-independent wave packet approach. Both methods give the same oscillation patterns, but only the latter one serves as a decent starting point for analyzing coherence in neutrino oscillations. A numerical analysis of the oscillation patterns on various distance scales is also given to graphically illustrate the phenomenon of neutrino oscillation and loss of co…
Search for a diffuse flux of high-energy ¿µ with the ANTARES neutrino telescope
2011
A search for a diffuse flux of astrophysical muon neutrinos, using data collected by the ANTARES neutrino telescope is presented. A $(0.83\times 2\pi)$ sr sky was monitored for a total of 334 days of equivalent live time. The searched signal corresponds to an excess of events, produced by astrophysical sources, over the expected atmospheric neutrino background. The observed number of events is found compatible with the background expectation. Assuming an $E^{-2}$ flux spectrum, a 90% c.l. upper limit on the diffuse $\nu_\mu$ flux of $E^2\Phi_{90%} = 5.3 \times 10^{-8} \ \mathrm{GeV\ cm^{-2}\ s^{-1}\ sr^{-1}} $ in the energy range 20 TeV - 2.5 PeV is obtained. Other signal models with differ…
Neutrino-nucleus scattering off 136Xe
2015
Background: Theoretical estimates of the cross sections for the neutrino-nucleus scattering off relevant nuclei for supernova neutrinos are essential for many applications in neutrino physics and astrophysics. The double- β-decaying nucleus 136Xe nucleus is used by the EXO Collaboration in the search for neutrinoless double-β decay. A ton-scale experiment based on 136Xe could also be used for studies of supernova neutrinos and/or solar neutrinos. Purpose: The purpose of the present work is, thus, to perform a study of the charged-current and neutral-current nuclear responses to supernova neutrinos for 136Xe. Method: The cross sections are computed by using the well-established framework for…
Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog
2021
Abbott, R., et al. (LIGO and Virgo Collaboration)
Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3a
2022
Abbott, R., et al. (LIGO and VIRGO Collaboration)
The advanced Virgo longitudinal control system for the O2 observing run
2020
Following a successful period of data-taking between 2006 and 2011, the Virgo gravitational-wave detector was taken offline for a major upgrade. The changes made to the instrument significantly increased the complexity of the control systems and meant that an extended period of commissioning was required to reach a sensitivity appropriate for science data-taking. This commissioning period was completed in July of 2017 and the second-generation Advanced Virgo detector went on to join the Advanced LIGO detectors in the O2 science run in August of the same year. The upgraded detector was approximately twice as sensitive to binary neutron star mergers as the first-generation instrument. During …